Car retarder



March 31, 1953 G. c. BELTMAN ETAL 2,633,210

CAR RETARDER Filed March 18, 1947 3 Sheets-s l March 31,1953

CAR RETARDER Filed March 18, 194'! G. C. BELTMAN ET AL [I II I i l II'lll'l 3 Sheets-Sheet 2 Ill/Ill March 31, 1953 G. c. BELTMAN ET AL CARRETARDER 3 Sheets-Sheet 5 Filed March 18, 1947 Patented Mar. 31, 1953CAR RETARDER George C. Bel'tman and Donald ,H. Sweet, Chicago, 111.;said Sweet assignor to saidBeltman.

Application MarchlS, 19432; SerialN 0.335315 I9'Claims; 1.

This. invention. relates. to the automatic controlof. the. speedofwheeled vehicles, and more specifically to. the automatic retardation ofvehicles not. otherwise controlled as, to speed; It includes. among itsobjects andv advantages the automatic, reduction of the. speed of thewheeled vehicle toa predetermined minimum definitely greater. than..zero, and. finds its chief field of usefulness inrailroadclassification yards.

lInthe, accompanying drawings:

Figure, 1. is a side elevation of a retarder unit according to. theinvention;

Figure 2 is a plan view of the same;

' Figure '3 is an end view of the retarder of Figure- 1. as on line 3-3of Figure 2;

Figure 4 isa side elevation of the cross beam forming a double pivot forthe beams of Figure l;

Figure.5 is an end. view of the same beam;

Figure 6 is a section through the dash pot of a retarder, on line 6-6 ofFigure 7;

Figure 7'is a section on line 'll of Figure 6;

Figure 8 is. a partly diagrammatic side elevation of one means forblocking up the beams when desired; and

Figure 9 is a similar view of a modified actuating means.

In. the embodiment of' the" invention selected for illustration, eachretarder unit is a pair of short rail sections inserted in both railsside by side. beam 40' and a short beam 42. As best indicated in Figures1" and 2', the beams 49 and 42 are inserted between lengths of ordinaryrail 44 and 4H and constitute a continuation of the rail" surface. overwhich. the. wheels of the car pass. Figure 1, the. contour of. the railsurface, hidden by the flanges of the beams, is indicatedv by the dot,and dash. line 45. In unloaded position the upper surfaces of the beams46 and 42 occupy the upper dot and dash line position of Figure 1 andpresent a short incoming section about 12 inches. longsloping. upwardabout an inch. to a maximum elevation. at 48,.anda longer section about54..inches long. The last six inches is level with. the fixed rail 45,and the remainder slopes up to join. the short section. The joints,between all. these sections are notched. as. best indicated. at 50 in.Figure 2, to transfer the wheel more smoothly from one section to thenext.

The. long. beam. 45 hasa fixed pivot 52 spaced aboutv 6. inches from thefixed rail 46, and supporting, hangers 411' formed in the upper flangesetoflthe beam. At the other end, the fianges54 end. in.downwardlyopening hangers; or. hookshaped' end portions 56,vwhichhoole-shaped por- Eachinsert section includes a long i timeoverlie: the loadbearing upper.- edge of. the carrier cross beam 53. Theshort beam 42' also has flanges. Bil extending throughout its. lengthand terminating, in similar hangers 6 I symmetrically spaced outside thehangers 55 and, riding on the same crossbeam 58. Adjacent the fixed rail44:, the flanges 50 have downwardly facing hangers 5| riding on struts62. on either side of the rail. 44, which struts rest, in. fixed.sockets 53. The flanges 54 and. both extend up about one and one-halfinches above the rail. This saves weight and also guards: against wheelsleaving the rail.

The articulate supportingmeans described permit the beams 40 and 42to'move down to bring the rail surface to the position of the lower dotand dash lines of. Figure l, with the apex. 48 about two inchesbelow thelevel of the rails 44 and 45.

It will be apparent thata wheel moving off. the rail 44 and encounteringthe beams in. the. lower dot and dash position will be subjected toantaccelerating force as it rolls down the beam 42 and to an equalretarding action as it subsequently rolls up along beam 40 so that itwill tend to return tothe rail 46 with they same speed as it had. whenit left the rail 44. However, if a wheel encounters the beams in theupper position and. rides part or all the way out to the apex ia-whilethe beams remain substantially in that position, it will not beaccelerated. And if the beams are then lowered substantially to thelower position, as by letting the cross beam.58, sink,.the sinking willnot accelerate the wheel but the subsequent climb up thelong beam 45will retard it.

The cushioning means for the cross beam 58 is both load sensitive andspeed sensitive and is best illustratedin detail in Figures 3 to 7.. Thebeam 58 is centrally notched down at the top as at 64 (see Figure 4) toclear the rail portions of the beams 49. and 42. Under each wing it hasa downwardly facing abutment surface 66, and projecting downwardly inthe middle is a strut 68 entering a dash pot indicated as a whole by thereference character 10.

A pistcnlz moves vertically in the cylinder 13', kept filled with liquidup to. the level indicated at 14 in Figured, as by means of aconventional float valve H. It has a guiding skirt l5 sliding freely inthe cylinder 13, and a plurality of grooves 18 for. collecting fluidworking up around the, skirt, whichfluidfiows back to the outsidethrough weep. holes'lfl, The top of the. piston has an upwardly-facingsocket receiving-the end of the strut 68. The peripheral wall of the cupcontains one or more threaded openings, each receiving a calibratingplug 82, which may be made up with central openings of various sizes. Alifting spring 84 is housed under the piston I2 and abuts the bottom ofthe dashpot. Air accumulating under the piston can exit through a weephole 11. The tension of the lifting spring 84 exceeds the weight of thebeams 40 and 42 by a proximately half of the load carried by one wheelof a. light or empty car, when the parts are in elevated position. Whenthe piston is depressed to the bottom of its stroke, the spring load maydesirably increase to about or A of the load of the wheel of a lightcar. Suitable means are provided for positively preventing the beamsfrom rising above the full line position of Figure 1, such as bolts 36anchored in the foundation and engaging the upper surface of the bottomflange 88 of the beam 49. A rin 89, held down by bolts 9|, facilitatesassembly by carrying the initial tension of the spring 84, when thestrut 68 is not effective for that purpose. Check valves 85 operate tolet the piston move up with relatively negligible damping action.

It will be apparent that a car wheel rolling along at 12 miles per hourwill travel the length of the short beam 42 in approximately of a secondand then spend more than & of a second passing over the long beam 40, ifit does not slow down. But the same wheel rolling along at 2 miles perhour will take six times as long on both beams, spending /3 of a secondon the short beam 42 and about a, of a second on the long beam 40. Andto depress the beams to their lowermost position in an 18th of a secondwill force the liquid in the dash pot to pass through the plug 82 sixtimes as fast as when the displacement takes place in of a second.Accordingly, the resistance of the dash pot to the fast downwardmovement will be greater than that oifered to the slow movement in theratio of about 36 to 1.

Thus the plug may be calibrated to oppose the fast movement withsufficient force to momentarily carry the load of the wheel to the endof the short beam 42 while only a small fraction of the completedownward displacement has occurred, and the rest of the displacementwill take place while the wheel is passing over the initial portions ofbeam 40. Thus a very light car go-, ing 12 miles an hour might pass overthe beam 42 while the fulcrum lowers a half inch and the fulcrum wouldgo down another inch and a half as the wheel covered about the firstfoot of the beam 40. Such a wheel would never have any downhill travel,climbing a slight incline most of the way across the beam 42 and beinglet down about an additional inch on the beam 48 and required to climbback up again.

But at the same speed a car of maximum weight might push the pivot downan inch and a half by the time it reached the end of the beam .42 andget down the full distance by the time it had covered about six inchesof the beam 4% It will be apparent that, traveling at the same speeds, aheavy car will be required to do materially more climbing than a lightcar so that both will be retarded but the heavy car will be retardedmore strongly.

However, when either a heavy car or a light car travels as slowly as twomiles an hour across the beam 42, there is ample time for the beams togo to substantially their lowermost position before the wheel hascovered more than a fraction of the length of the beam 40. And undersuch circumstances substantially the entire ef feet on the wheel will beto let it roll downhill and then uphill to the same verticaldisplacement without material retardation. And at all intermediatespeeds throughout the range, the timing of the dash pot action will makeit effective to exert a retarding action substantially proportional tothe square of the speed of the car.

Cut-out controls After a train has been assembled, it is customary to gointo the yard with a locomotive and bring the train out at the same endwhere it was put in. An ideal installation might be provided withtrackage at the other end to take the trains out, but in any practicalinstallation it will be necessary to bring the cars back out at the sameend occasionally, and in present yards that is common practice. When atrain is being taken out over the gravity retarders, it is undesirableto have either the locomotive or the cars operate the gravity retardersalthough, at reasonable speeds not exceeding 15 miles an hour, the maineffect would be only to jounce the cars up and down a little.

Referring to Figures 1 and 8, the abutments 66 of the cross beam 58,when the parts are in elevated position, are spaced three inches fromfoundation abutments indicated in Figure l at 93, which abutmentsfunction as a stop to limit the downward movement. A blocking yoke isprovided comprising end blocks 92 and a cross reach 94 curved back toallow clearance for the strut 68. The yoke is normally held in theposition of Figure 1 by light tension springs 95. The blocks 92 are-twoinches high, and may be drawn across under the abutment faces 66 so thatdownward movement of the beams is limited to a position where theypresent a level track. The parts may be drawn into blocking position bya pair of tension rods 96.

Means are provided for actuating the tension rods 96 in two differentways. An automatic actuating means is illustrated in Figure 8 andincludes a plate 98 about 36" long, lying beside the wheel-carryingsurface and extending on both sides of the pivot 52. The plate is heldin the position of Figure 8 by a pair of compression springs I00, one ateach end, encircling guiding bolts I02. The guiding bolts pass throughstationary guide blocks I04 apertured to leave substantial clearancearound the bolts to permit free movement of the plate. Washers I06 heldin place by nuts I08 limit upward movement of the bolts I02. A bellcrank lever HE] is pivoted at Hz and has one arm underlying the lefthand bolt I02 and a vertical arm apertured to receive a tension rod I I4loosely. Springs H6 and abutments I I8 on the rod I I4 provide aresilient lostmotion connection between the bell crank III! and thetension rod H4. The other end of the tension rod. connects with theupper end of a vertical catch lever I29 having a hook I22 movable tocatch under the corner of a housing I24 on the right hand bolt I112. Thepivot I26 for the catch-rod I20 is carried by a horizontal arm I21 on ashaft I28. The shaft I28 has a downwardly extending arm I30 receivingthe tension rod 96 loosely. The tension rod has abutments I32 at its endand springs I34 between the abutment and the arm I30, which springs aretwo or three time as stiff as the springs pulling on the yoke 94 in theother direction.

1 Itaisxapparent thatpa wheel coming fromrthe left asviewedi inFigura 8wiil first. depress the .lefinend; of the plate as... which will.fulcrum around-the rightzendabutment IM. This. down.-ward:movementiwillarocli.therbeil; cranlrlever II B' and? pull onthe.tension; member I:I 4: and-swin thecatchlevenoverunder thehousing I24...This conditionwill.continuewhile the wheelcontinues to. the. middle; oftheP-plate; 9.8: and the: housin the. load (lithe; wheeL on: the beamand; .on the.

abutment-(faces. 66; so that byrtheatimather. wheel leaves the; plate..93; the. blocks. 92: are.

ripped, byxtheweightzoff the; wheel; passing over;

and: remain. that; condition until. the wheel" leavespthebeamjz .lnrthevmeantime, the parts have: returned. to. the initial position. so; that.as

$001.11 as: the spring: at; begins to. lift the beams backin the. yoke.-s4 and, blocks ezhcan move back to: the position of Figure 11 under:the: unopposed'forcaof' thespringsefi.

It; is also; apparent that alwheel'. traveling in the other direction,..after it; has traversed both beams; either with or without being;retarded thereby, will: depressfirst' theisright' hand end of plate:9.8! and then' the. left: hand. end. The. first depression: will move;theliousing I24 downheiow .the;.1hoolc I22. and. the second depressionwill merely" compress: one. of the springs. II'G a little and cause thetoe of the hook I22 to press lightly againstathahousing I24. But:nothing willhappen. to": the. blocks 92, so that a following wheelbathe; same truck or another carcoupled to the carwhich hasjust passed:will find" the entire device. ready to. function and effect whateverre-- tardation the speed and load of" the'next wheel callsafor. I

Referring: to. Figure 8, I have indicated a stringer, or" pipe, I38,which maybe connected tozth'ezends of the dependinglevers I30 of aplurality cofzgravity retarders by means. of drag operating the blocks92; The swinging control.

lever" hi2 normally occupies the; full line position oil ligure 9-,being held in contact withpivot-IM.

byrlightasprings: M'fi'strongenough: to carry the weightzof the leverand associated. parts-. The:

upper end of the lever projects about 2"" above the rail level, in. theplane: of the wheel flanges, and carries a contact roller I48 to engagethe: wheel flanges. In-the fullline position, the fixed pivot I44 liesin: the. lower-apex of a. V-shaped' slot: Ifl'3 inthe lever I42. Itwillbe apparent that the initial contact of awheel coming from the leftandengaging theroller |48wi1l tend to push the lever down until the pinI44 reaches the'end of the left arm of theV', after which furthermovement. will carry the roller I48 down to the right: andact throughthe springs I50 to pull on the tension member 96.

a However; a. wheel coming from the opposite direction: will tilt thelever I42 a counterclockdirection, which will either; do nothing tothetablocksaazi .orv-will push them a little further out; of'blockingposition. With. the modification of Figure 9 it is necessary toconnect the lever I42 through flexible tension. cords. I.52;so. that theautomatic operation .is not'interferedwith by the. connection for manualoperation.

Retarders of the conventional. side friction type are insensitive toboth speed and load. Theycan do more retarding in a given distance thangravity retarders' according to the invention, but because the frictiondepends on the condition of" theside surfaces of the wheels, itis out ofthe question tosecure uniform or precise-results with them. However, aside friction retarder need only get the incoming cars down to anythingbetween about live and about twelve-miles per hour, and gravityretarderscan. finish the job witlrp-recisi'on.

A complete new installation: with gravity re-- tarders mayadvantageously employ: a hump-of materially reduced" height, and do allthe re-- tarding by gravity. This. does away with many maintenanceproblems. In such an installation the: retard'ers on the-hump and in theswitching section need to be set for much higher speeds.

Others may readily adapt the invention foruse under various conditionsof service by employing one or more of the novel features disclosed, orequivalents thereof. For instance, in gravity retarders for high speedoperation on the hump, it will be advantageous to increase thelength ofthe beam 42 by from 50% toand in any gravity retarderthat will be calledon to move its plunger down. with more than half the acceleration ofgravity, hangers on the cross beam should be connected to the crossbeam, to follow it down without separation.

The preferred fluid for the. dash pot is primarily water, but. inclimates where freezing temperatures are experienced, the. water shouldbe protected by a. conventional anti-freeze com.- pound, preferably onewith a higher. boiling point than waten such as diethylene glycol. Whena yard is active, the energy absorbed by the dash pots will. keep the.contents boiling hot and evaporate substantial quantities of. water. Buteach heat increment will appear in the body of liquid at a point outsidethe cylinder Where the liquid jet issues from the cylinder, so that itwill not be difficult to make the reservoir surrormding 1the cylinder ofadequate area for. steam liberaion.

As at presentadvised, with respectto the. apparent scope of ourinvention, wedesire to claim thefollowing,subjectmatter:

1. In a railroad carretarder, incombinati'onx: spaced. fixed, railsections positioned with. a. gap between them two longitudinallyaligned'jbeams, together. bridging said gap; the one ofsaidjbe'ams atthe end identified as. the, entrance. end being shorter than the other;a common pivotal sup.- port for the. adjacent ends ofsaid. beams;individual pivotal supports for the. remote ends. of said beams; saidindividual supports being positioned to hold the remote; ends of said.beams substantially level with the adjacent track said joint pivotal.connection being. vertically movable; hydraulic' dashpot mean connected.to said joint pivotal connection and adapted. toabsorb a;- maximumamount of. energy during downward movement and a relativelynegligibleamount-of energy during upward movement; spring means biasing said jointpivotal connection upwardly; and stop means limiting the-action of'saidspring meansto aposition: in which the parts are post-.

tioned for a full downward stroke of said dashpot.

2. In a railroad car retarder, in combination: spaced fixed railsections positioned with a gap between them; two longitudinally alignedbeams, together bridging said gap; a common pivotal support for theadjacent ends of said beams; means for guiding said joint pivotalconnection in movement in a predetermined path between an upper positionand a lower position; hydraulic dashpot means connected to said jointpivotal connection and adapted to absorb a maximum amount of energyduring downward movement and a relatively negligible amount of energyduring upward movement; spring means biasing said joint pivotalconnection upwardly; and stop means limiting the action of said springmeans to a position spaced from said lower position.

3. In a railroad car retarder, in combination: spaced fixed railsections positioned with a gap between them; two longitudinally alignedbeams, together bridging said gap; pivotal supporting means for theadjacent ends of said beamsysaid pivotal supporting means guiding saidadjacent ends in movement in a predetermined path between an upper and alower position; hydraulic dashpot means connected to said supportingmeans and adapted to absorb a relatively large amount of energy duringdownward movement and a relatively small amount of energy during upwardmovement; and means biasing said supporting means upwardly toward saidupper position.

4. In an automatic railroad car retarder, in combination: spaced fixedrail sections positioned with a gap between them; a plurality ofvertically movable sections articulated to each other and to said fixedrail sections to receive and support the entire weight of a car wheel tobe retarded; hydraulic dash pot means underlying and connected tocertain of said movable sections; said dash pot means having apermanently open vent and another vent provided with an inwardly openingcheck valve; and resilient means biasing said sections upwardly when notunder load; said permanently open vent being small enough to cause saiddash pot to temporarily support the entire weight of a car wheel movingat a speed in excess of three miles per hour.

5. In an automatic railroad card retarder, in combination: spaced fixedrail sections positioned with a gap between them; and a plurality ofvertically movable sections articulated to each other and to said fixedrail sections to receive and support the entire weight of a car wheel tobe retarded; hydraulic dash pot means connected to certain of saidmovable sections; said dash pot means having a permanently open vent andanother vent provided with an inwardly opening check valve; andresilient means biasing said sections upwardly when not under load; saidpermanently open vent being small enough to cause said dash pot means totemporarily support the entire weightof a car wheel moving at a speed inexcess of a predetermined maximum safe coasting speed at which a car canbe stopped by impact with standing cars without injury to the contentsof the car.

6. In an automatic railroad car retarder, in combination: a plurality ofvertically movable rail sections articulated to each other andpositioned to receive and support the entire weight of a car wheel to beretarded; hydraulic dash pot means connected to certain of said movablesections; said dash pot means having a vent; and resilient means biasingsaid sections upwardly when not under load; said vent being small enoughto cause said dash pot to temporarily support the entire weight of a carwheel moving at a speed in excess of a predetermined maximum safecoasting speed at which the contents of the car will remain undamaged bystoppage of the car by impact with other cars standing still on the sametrack.

7. Equipment for automatically controlling the speed of a railroad cartraveling on conventional rails, comprising, in combination with a fixedrail surface: a movable section interpolated in the rail surface; saidsection having an entrance end and an exit end; means for supporting theexit end of said section at all times substantially level with thecontinuation of said rail surface; the entering end of said sectionbeing vertically movable and normally at a predetermined level withrespect to the adjacent fixed rail surface; means supporting saidsection in undisturbed position with a force materially less than theweight normally imposed on said section by a car wheel; stop meanslimiting the downward movement of the inlet end of said section to apredetermined maximum; and means for absorbing and dissipating energy inretarding the downward movement of said inlet end; said absorbing meansbeing adapted to resist downward movement with a variable forceapproximately proportional to a higher power, not less than about thesquare, of the speed of the downward movement.

8. Equipment for automatically controlling the speed of a railroad cartraveling on conventional rails, comprising, in combination with a fixedrail surface: a movable section interpolated in the rail surface; saidsection having an entrance end and an exit end; means for supporting theexit end of said section at all times substantially level with thecontinuation of said rail surface; the entering end of said sectionbeing vertically movable and normally at a predetermined level withrespect to the adjacent fixed rail surface; means supporting saidsection in undisturbed position with a force materially less than theweight normally imposed on said section by a car wheel; stop meanslimiting the downward movement of the inlet end of said section to apredetermined maximum; and means for absorbing and dissipating energy inretarding the downward movement of said inlet end; said absorbing meansbeing adapted to resist downward movement with a variable forceapproximately proportional to a higher power, not less than about thesquare, of the speed of the downward movement; said absorbing meanscomprising a hydraulic dashpot.

9. Equipment for automatically controlling the speed of a railroad cartraveling on conventional rails, comprising, in combination with a fixedrail surface: a movable section interpolated in the rail surface; saidsection having an entrance end and an exit end; means for supporting theexit end of said section at all times substantially level with thecontinuation of said rail surface; the entering end of said sectionbeing vertically movable and normally at a predetermined level withrespect to the adjacent fixed rail surface; means supporting saidsection in undisturbed position with a force materially less than theweight normally imposed on said section by a car wheel; stop meanslimiting the downward movement of the inlet end of said section to a J29predetermined ;.maximum; and; means for' absorbing anddissipatingenergyin retardin the downwardmovement of said inlet end.

1.0,. Equipment for .automatically controlling the speed of a railroadcar traveling on conventionalrails, comprising, incombination with afixedzrailsurface; a movable section interpolated in the-rail surface;saidsecticn havingan zen- 'trance-zendirandaan exit end; means iorsupporting the: exit end :of said section at all times substantially,level with the continuation of said rail surface; the entering end ofsaid section being vertically movable and V normally at a predeterminedlevel with respect to the adjacent fixedmailsurface; means supportingsaid section in iundistmbe'd position with v a force materially less.athan :the :weight normally imposed on said section by aicar'wheel; stopmeans limiting the downward imovement of the (inlet end of saidsectionirto a predeterminedzmaximum; andmeans for absorbingranddissipating energyinretarding the downward movementiof .said'inlet end;said absorbing means being adapted :to resist downward- :movement with.a variable force approximately 'proportionallto aihigher power, notless thaniabout thesquare, .ofthe speed of the downward movement; saidabsorbing meanscomprising. ahydraulic-dashpot; the entering ,end ofsaidsection being normally materially above the fixedl -rail surface andvmovablefrom its uppervmostpositiondownwardly below said rail Surface.

1:11. z'Aitrack .retarder for railroad rolling stock comprising, incombination: a first track section,

identified as "a receiving section, supported at a substantiallyponstantlevel at one end, identified as the :receiving end; a second relativelylong trackzsection adjacent saidfirst section and identified as adelivery section; said delivery section .havingqadelivery end remotefrom said receiving section supported at a substantially constant level;said receiving and delivery sections having their proximate endsinsubstantial abutment; said proximate ends being articulated togetherabout a common taxis; resilient :mean :normally supporting said "commonaxis in position :to .hold the :proximate :ends of said sections a1predetermined idistance above a straight line joinin rthe remoteends-of said sections; stop means limiting upward'movement. of said axis1 stop means limiting; .:.the downward :movement of said axis to abottom positionspaced below astraightline ,j oining the ends cofgsaid.sections by a distance about twice as. great as. the upward deviation inthe uppermost gposition of said axis; and damping means: for absorbingand dissipating ,energyin resisting downward displacement of said axis;said adamping means operatinghydraulically to oppose downward movementofsaid axis with a force approximately proportional \to .a higher power,:not less than two, of the :speed of downward movement; said means forlimiting downwardzdisplacement of said "axis including garfixed abutmentand :a co-operative .cabutment movable downward with said axis; meansfor raising :the eflective level -:.of .said :fixed abutment .to ;limitdownwardunovement of isai'd :axis :to azposition where said sections arein a "straight ,line, saidraiisingrmeanscomprisinga:movable:block:adaptedjrto be interposedbetween said abutments when they are sufficiently separated; gmanualmeans formoving said raising'means into operative posi tie and:automatic means rendered ioperative byentryiof 2a 'wheel travelingrinreversezdirection, tormoving said raising"meansinto,operativexposition:\asaid -zautomaticxmean zincludingeatmovable element adjacent thedelivery end of said-long section and :Positioned to bedisplaced in onesense bya wheelmoving-in-one directionrand in an opposite sense by awheel moving .in the-ope posite direction; and a connection foractuating said raising means upon displacement of said movable elementin one sense, but not by displacement in the. opposite sense.

12. A track retarder for railroad rollingstock comprising, .incombination: rat-first track section identified as a receiving sectionsupp rted at a substantially,constantlevelat one end, identified as vthereceiving end; a second relatively long track section adjacent saidfirst section andidentified as a delivery section; said delivery sectionhaving a delivery endremote from said receiving section supported at asubstantially constant level; said receiving anddelivery sections havingtheir proximate ends in substantial abutment; said proximate end beingarticulated together about a common axis; resilient means normallysupporting saidcommon axis in position to hold the proximate ends 'ofsaid sections a predetermined distance above a straight line joining'theremote ends of said sections; stop means limiting upward-movement ofsaid axis; stop means limiting the downward movement of said axis to abottom position spacedbelow ,a straight line aoining the ends of saidsections by a distance about twice as great as the upward deviation {inthe uppermost position of said axis; anddamping means resisting.downward displacement of said axis; said dampingmeans'for absorbing andd s ipatine en gy operating hydraulically to QPpOse downwardmovement ofsaid axis, :with a force approximately proportional to a higher power,notless than tWQ,,10j thespeed .of down- Ward movement; saidmeans-iorfimiting downward displacementofsaid axis including a fixedabutment and a .co-operati-veabutment movable downward'with said axis;means for raisin the efiective level of :said fixed abutment to limitdownwardmovement of said axis to a position where said sections are in astraightline; and automatic means including a movable element adjacentthe delivery end of saidlong sectionand positioned to bedisplaced in onesense ,bya wheel moving in one direction andin an-opposite sense by awheel moving in the opposite direction a n,d a connection for actuatingsaid raising means upon displacement of said movable elementdn one sensebut motby displacement 11in 'thebpposite sense.

:A track retarder for wheeled vehicles comprising in combination: twoadjacent trackzsece trons, having their proximate ends insubstantialabutmentand verticallymoyablerthe remotesends of said sections beingsupported at substantially constant :level; resilient means normallysupportmg said -proximate ends ginua predetermined elevated positionwhen not under load; stop :means positively limiting the downward:movement :of saidproximate endsyanddamping meansaiorabscribing-randdissipating lenergyaduring downwarddisplacement:ofsaidproximateendsgbutanotduring upward returntosaidmredetermined elevated position.

314. In an automatic railroad .Gar'retarder. in combination: avertically movable rail section positioned to receive and support theentire weight :of ;a.- car wheel ztogbe retarded; hydraulic dashpotmeans -;eonne,c,ted :to said section; :said dashpot meanshaving 5a vent;and resilient means biasing said section upwardly when not under load;said vent being small enough cause said dashpot to temporarily supportthe entire weight of a car wheel moving at a speed in excess of apredetermined maximum safe coasting speed.

15. Equipment for automatically controlling the speed of a railroad cartraveling on conventional rails, comprising, in combination with a fixedrail surface: a movable section interpolated in the rail surface; saidsection having an entrance end and an exit end; means for supporting theexit end of said section at all times substantially level with thecontinuation of said rail surface; the entering end of said sectionbeing Vertically movable and normally at a predetermined level withrespect to the adjacent fixed rail surface; means supporting saidsection in undisturbed position with a force materially less than theweight normally imposed on said section by a car wheel; stop meanslimiting the downward movement of the inlet end of said section to apredetermined maximum; and means for absorbing and dissipating energy inretarding the downward movement of said inlet end; said absorbing meansbeing adapted to resist downward movement with a variable forceapproximately proportional to a higher power, not less than about thesquare, of the speed of the downward movement; said absorbing meanscomprising a hydraulic dashpot; the entering end of said section beingnormally materially above the fixed rail surface and movable from itsuppermost position downwardly below said rail surface; said movablesection being combined with another movable section adjacent itsentering end; said sections being articulated at their remote ends atthe level of the adjacent fixed surfaces; said sections beingarticulated to each other at their proximate ends.

16. Equipment for automatically controlling the speed of a railroad cartraveling on conventional rails, comprising, in combination with a fixedrail surface: a movable section interpolated in the rail surface; saidsection having an entrance end and an exit end; means for supporting theexit end of said section at all times substantially level with thecontinuation of said rail surface; the entering end of said sectionbeing vertically movable and normally at a predetermined level withrespect to the adjacent fixed rail surface; means supporting saidsection in undisturbed position with a force materially less than theweight normally imposed on said section by a car wheel; stop meanslimiting the downward movement of the inlet end of said section to apredetermined maximum; and means for absorbing and dissipating energy inretarding the downward movement of said inlet end;

said absorbing means being adapted to resist downward movement with avariable force approximately proportional to a higher power, not lessthan about the square, of the speed of the downward movement; saidabsorbing means comprising a hydraulic dashpot; the entering end of saidsection being normally materially above the fixed rail surface andmovable from its uppermost position downwardly below said rail surface;said movable section being combined with another movable sectionadjacent its entering end; said sections being articulated at theirremote ends at the level of the adjacent fixed surfaces; said sectionsbeing articulated to each other at their proximate ends; said means fordissipating energy being a hydraulic dashpot connected to the proximateends of said portions. 7

17. Equipment for automatically controlling the speed of a railroad cartraveling on conventional rails, comprising, in combination with a fixedrail surface: a movable section interpolated in the rail surface; saidsection having an entrance end and an exit end; means for supporting theexit end of said section at all times substantially level with thecontinuation of said rail surface; the entering end of said sectionbeing vertically movable and normally at a predetermined level withrespect to the adjacent fixed rail surface; means supporting saidsection in undisturbed position with a force materially less than theweight normally imposed on said secs tion by a car wheel; stop meanslimiting the downward movement of the inlet end of said section to apredetermined maximum; and means for absorbing and dissipating energy inretarding the downward movement of said inlet end; said absorbing meansbeing adapted to resist downward movement with a variable forceapproximately proportional to a higher power, not less than about thesquare, of the speed of the downward movement; said absorbing meanscomprising a hydraulic dashpot; the entering end of said section beingnormally materially above the fixed rail surface and movable from itsuppermost position downwardly below said rail surface; said movablesection being combined with another movable section adjacent itsentering end; said sections being articulated at their remote ends atthe level of the adjacent fixed surfaces; said sections beingarticulated to each other at their proximate ends; said means fordissipating energy being a hydraulic dashpot connected to the proximateends of said portions; the articulation of the exit end of said longportion being fixed; the other two articulations permitting slightlongitudinal movement to compensate for the angularity of said portions.

18. A track retarder for wheeled vehicles comprising, in combination:two adjacent track sections having their proximate ends in substantialabutment and vertically movable; the remote ends of said sections beingsupported at substantially constant level; resilient means normallysupporting said proximate ends in a predetermined elevated position whennot under load; stop means positively limiting the downward movement ofsaid proximate ends; damping means for absorbing and dissipating energyduring downward displacement of said proximate ends, but not duringupward return to said predetermined elevated position; said stop meanscomprising a fixed abutment and a co-operating abutment movable downwardwith said proximate ends; and means for changing the effective level ofsaid fixed abutment to limit downward movement of said axis to a bottomposition at a higher level; said means comprising a movable blockadapted to be interposed between said abutments when they aresufficiently separated.

19. A track retarder for wheeled vehicles comprising, in combination:two adjacent track sections having their proximate ends in substantialabutment and vertically movable; the remote ends of said sections beingsupported at substantially constant level; resilient means normallysupporting said proximate ends in a predetermined elevated position whennot under load; stop means positively limiting the downward movement ofsaid proximate ends; damping means for absorbing and dissipating energyduring downward displacement of said proximate ends, but not duringupward return tosaid preinoperative automatic means for interposing said10 1,359,073

block between said abutments; and connections actuated only by a wheelmoving in one predetermined direction, for rendering said automaticmeans operative.

GEORGE C. BELTMAN. DONALD H. SWEET.

14 REFERENCES CITED The following references are of record in the fileof this patent:

UNITED STATES PATENTS Number Name Date 806,147 Hussey Dec. 5, 1905813,542 Case Feb. 2'7, 1906 1,560,878 Tatum Nov. 10, 1925 Clausen May17, 1932 FOREIGN PATENTS Number Country Date 481,115 Great Britain Mar.4, 1938

